Optical projecting apparatus.



E. SCHNEIDER.

oPTwA'L PROJBCTING APPARATUS. j 1` PPLATION ILED NOV.2B,1908. 953,1 05. Patented Mar.

3 SHEETS-SHEET 1.

| l l l l l l E. SCHNEIDER.

OPTICAL PROJBGTING APPARATUS.

APPLICATION FILED NOV.28,1908.

1 Patented Mal'. 29, 1910.

" a SHEETS-SHEET 2,

E. SCHNEIDER.

OPTICAL PROJEGTING APPARATUS.

APPLIUATION FILED NOV. 28, 41908. 95 3, 1 05, Patented ,Man 29, 1910.

3 SHEETS-SHEET 3.

" UNITED STATES PATENT orales.

EBEBHARD SCHNEIDER, OI`NEW YORK, N. Y.

OPTICAL PEOJEGTING APPARATUS.

To all whom it may concern:

B e' it known that I, Essai-IARD SCHNEIDER, a citizen of the United States, residing at New York,.in the county of New York and State of New York, have invented. certain new and useful Improvements in Optical Projecting Ap aratus, of which the following is al specication, reference being had to the drawings accompanying and forming.`

part of the same.

This invention relates 4to projecting apparatus, more particularly ot the so-called dissolving view, type, in which the picture on the screen is mad'e to fade away concurrently with the gradual appearance of jthe 'succeeding picture. In ap aratusv of this as hitherto constructs ty the dissolving egt is usually produced b manipulation of the lights Iin two adjacent anterns. Thus while a picture in one of the lanterns is thrown on the screen with full brilliancy the slide bearing the next picture to be exhibited is inserted in the other lantern, the

light of`which isofcourse extinguished or se dim as to be practically extinguished; the

. light in the first lantern is then diminished 1 gradually, while the li ht in the second is 4 gradually increased, wit the result that the necessitate relighting, with possible delay and confusion in the orderly progress of the exhibition, and without in the' other case makin the flame too intense, which might result 1n fracturing the lime. Where the electric arc is employed the operation is even more difficult, as the operator has not only to control the intensity of the lights but also to. keep the carbone at the proper distance apart and keep each arc at the focus of its condenser. -I have therefore been led to devise my pre-ent invention, which has for its chief object to lprovide a projecting apparatus which wi give' satisfactory dissolvin -view e'ects wlth a single source of 1i t ept continuously at ful brilliancy. .T us the principal source of trouble, to wlt,

i Specication et Letters Patent,

Application tiled November 28, 1908. Serial No. 464,928.

Patented Mar. 29, 1910.

the manipulation of two sources of light simultaneously, is eliminated.

In carrying out my invention in the preferred manner the two objectives are mounted one above the other, or side by side, as may be most convenient, and each has its own condensing lens as is customary. Back.4 ofthe condensers-is the lantern body or li ht chamber, in which is a single source of lig it, say a calcium light or an electric arc, arranged in the plane which passes midway between the two condensers, or as close to said plane as is practicable. Adjacent to each condenser I arrange one o1' more glass prisms of triangular cross-section, disposed with their bases' adjacent to each other. The effect of the prisms is to deflect the light, from the single source, in two beams directly into the respective condensin lenses.

Two screens or shutters `are provi ed, ar-

ranged to cut off the 'lightto either or both conc ensers at will', so that either picture can bfe (projected, and provision is mac e whereby' 1 esired the actuation of a single o erating member will-close one shutter as t ey o the'r opens, and vice versa.' Thus by the manlpulation of a single member, with the light at full brilliancy at all times, the operator can throw the light in to the condensers alter.- nately; and since the shutters can beoperated at' any desired speed of movement the.` light can be thrown into one condenser and cut ofi' from the other as gradually and evenly as desired. In this way very satisfactory and pleasing dissolving effects can be obtained. l

It will be a parent to those skilled in the nrt that the sc 1eme thus briefly outlined can be embodied in various constructions. `Of theseV l have selected for illustration and specific description herein two arrangements which exhibit the invention in convenient und effective form.

Referring now to the drawings, Figure 1 is a lon itudin'al sectional view of the ferred, crm of the invention. Fig.'2 1s a similar view of another form. Figs. 3 and 4 are .sectional views on lines II-II and III-III respectively, of Fi". 2.

Throughout the various an electric arc light, the two `carbone ne Egures, 1 desig- 105 natos a lantern body, in front of which are held by two adjustable holders 4,5, carried by vertical rack-bars 6, 7, in mesh with a pinion (not shown) whichl is rotated by a hand wheel 8 projecting to the rear of the lantern. The parts just described are supported on a rod 9a by any suitable devices, not shown, to permit vertical, lateral, and longitudinal adjustment, so that the arc can be located at any desired point with respect to the objectives and other partsy hereafter to be described. Since devices for effecting such. adjustments are well known in the art, and since the same are not a part of'my present invention, further description thereof is unnecessary. ln front of -the light is the usualheat screen 9, extending to the chimney 10. The slide carriers 11, 12, are arranged in front of the forward wall of the lantern body, as is customary; said wall of course having suitable openings to permit the passage of light, as shown.

Referring now to Fig. l, behind the slide carriers are the condensers 13, 14, each, in the present instance, composed of two planorconvex lenses arranged with their convex surfaces toward each other, and supported in any convenient and suitable manner. The condensersiserve their usual purpose,

" to convergefor condense, the light through the picture-slides into objectives. Back of the condensers are two triangular prisms 15, 16, preferably of the rightangled type shown, arranged with their inclined surfaces towardthe condensers, and with their bases horizontal arid parallel. This makes the rear faces of the prisms vertical and therefore more nearly perpendicular to the rays'of light, so that as much light as possible will enter the prisms and as little as possible be reflected. The prisms are adjustable toward and from the condensers, on the rod 9, and their supporting members 17, 18 are hinged together, as shown, so as to permit slight angular adjustment. Back of the prisms are two hinged shutters, 19, 20, and journaled in the side of the lantern (see Fig. 3) is an operating lever 21, the arm 22 of which is off-set at 23. This lever is movable axially in its bearings, and when the same is drawn out, as shown in dotted lines in Fig. 3, it will be disengaged from shutter 19, but its off-set portion will still be in engagement with the lower shutter, 20. On the latter is guide yoke 24, arranged over the olf set portion of the lever.

From the foregoing description the operation of the apparatus will be readily understood. The parts being in the positions shown in Figs. 1 and 3, the operator inserts a pictureslide in the lower slide-carrier, and then raises the lower shutter by turning the operating crank up and to the rear until the lower shutter is parallel with the up* er,-the latter of course being kept closed y the shaft-portion of the operating lever.

While the lower picture is on the screen the next slide to be exhibited is inserted in the upper carrier, and at the proper time the operator draws the operating lever out, thereby disengaging the same from the upper shutter, and turns the crank back to its original position. This movement returns the lower shutter, cutting od the light from .the lower prismybut at the same time the upper shutter, being disengaged from the obseuring the upper. If at any time he desires to cut olf the light from both prisms, the shutters are brought to the upper posi tion and the operating lever pushed in, reengaging the upper shutter. The lower shutter can now be lowered without the i other following it, as in Figs. 1 and 2. The effect of the prisms, as previously stated, is to bend the light rays into the condenser-s. By properly shaping the prisms, with due regard to the refractive index of the glass or other transparent medium employed, the raysk may be made to strike the condensers substantially parallel with the axes thereof, instead of at a wide angle as would be the case without the prisms, in which case only a comparatively small proportion of the light would be directed into the objectives. In the construction illustrated in Fig. 2 the prisms, 151, 16a, are of the isosceles type and are located between the lenses of the condenser-s2 the rear condenser lenses 25, 26, being inclined toward the source of light so that the rays will strike the plane surfaces thereof at substantially right angles. rl'he rays are thus converged upon the' prisms, and are bent or refr-acted thereby into the front condenser lenses 27, 28. Back of the rear condenser lenses are the shutters 19, 20, like those illustrated in Fig. 1, and operated by similar mechanism. In Fig. 2

the source of light is shown much below its best position, in order to indicate the adjustability of the source. In use the carbons would be raised until the are is about in the central horizontal plane.

The refraction of the light by the prisms of course results in slight dispersion, butby reason of the considerable distance of the screen from the objectives and the consequently great elongation of the spectrum the colors are so thinned out, so to speak, as to be unobjectionable if noticeable at all. lVith colored slides the spectrum colors are imperceptible.

It will now be seen that my invention eliminates a large part of the work of the lmore attention to the care and disposition of the slides, to maintaining the light in good condition and keeping it at the proper position With respect to the optical elements lofthe apparatus, etc. Although the source of light is kept at full brilliancy it is evident that a slngle source burning continuously will consume practically no more gas or current lthan twol lights burning in alternation.

As previously stated, the forms herein specifically described are given as convenient and effective embodiments and not as the only embodiments of which the invention is capable. vMoreover, the details of construction in the forms herein shown may be varied widely without departure from the proper spirit of the inventionl asdelined by the appended claims.

That I claim is:

'1. Inan optical projecting a paratus, the combination With lens systems fidr projecting the pictures, and a source of light, of means .for altering the paths of the rays from said source toward parallelism with the axes of said lens systems, shutters movable in unison or separately, as desired into and out of the paths of said rays, and manual means common to said shutters for operating the same, as set'forth.

2. 1n an optical projecting apparatus, the i' combination with projecting objectives, and a source of li ht, and condensing lenses between said objcctives and the source of light, 'of refracting prisms associated with said condensing lenses and arranged to refract the rays of light from said source toward parallelism with the axes of said condensing lenses, movable shutters in the paths otl said rays, and manual means common to said shutters for operating either shutter at will, as set forth. j

3. In an optical projecting apparatus, the combination of a pair of` rejecting systems, a source of light behindp and midway be 'tween said systems, shutters hinged midway between said systems, and manual means common to both said shutters for swinging eitherof Said shutters at will into or out of the path of the light through its respective projecting system, as set forth.

4. In an optical projecting' apparatus, the combination with a pair of substantially parallel projecting systems, of a pair of hinged shutters, and an operating lever in4 constant operative engagement with one of said shutters and adjustable into and out of engagement with the other, as set forth.

In an optical projecting s stem, the combination with a pair of substantially parallel projecting systems, of a pair of shutters hinged at their adjacent edges whereb to be swung into and out of the path o light rays through said s stems, and a manual operating lever for t e shutters fulcrumed adjacent to the shutter hinges, as set forth. l

6. In an optical projecting apparatus, the combination of a pair of lens systems for projecting pictures, a single source of light behind (he same, refracting )risms arranged to refract the light from sai source into the lens systems, supports for the prisms, and a common supporting member on which said supports are pivotally mounted to permit angular adjustment of the prisms, as set forth.

7. ln an optical projecting s stem, the combination of a pair of su stantially )arallel lens systems, a single source of light behind the same, a pair 0i rods parallel to and in the rear o1 said lens systems, retracting prisms for rclracting the rays of light from said source into the lens systems, pivotal primi-supporting devices mounted on one ot said rods to permit angular adjustment of the prisms, and means for cutting o'tl the light to either lens system at will, as sel. forth.

EBERUARD St'll-lNlJlDER. ll'f'itnesses M. Lawson Dran, S. S. lli'JMmm'. 

